Preheat oven to 325 degrees F (165 degrees C). Lightly grease a medium baking dish.
Melt margarine in a medium saucepan over medium heat. Place onions and celery in the saucepan. Slowly cook and stir until tender.
Place bread in a large bowl. Toss in poultry seasoning. Stir in the onion and celery mixture. Mix in eggs and stir until all ingredients are moist and coated.
Transfer mixture to the medium baking dish. Cover and bake in the preheated oven 20 minutes, or until lightly browned.
